Beryllium-bronze alloy



United States Patent 3,150,969 BERYLLIUM-BRONZE ALLOY Ellsworth M.Smith, Reading, Ya, assignor to The llruslr Beryllium Qoinpany,Cleveland, Ohio, a corporation at Ohio No Drawing. Filed Dec. 17, 1962,Ser. No. 244,862 3 Claims. ((31. '75--153) This invention relatesgenerally to beryllium-copper alloys, and more particularly toberyllium-copper alloys containing zinc, cobalt, and optionally tin.

Hereinafter, all reference to percentages of ingredients are percentagesof the total weight of the compositions.

it has been well established in the beryllium-copper alloy art thatcopper-based alloys containing beryllium and minor proportions of eithercobalt, nickel, or mixtures thereof, upon being cold Worked, as byrolling, and subsequently solution annealed, quenched, and heat treatedin a temperature range of about 600 F. to about 800 F., developed hightensile strength, excellent fatigue endurance, excellent wearresistance, and good electrical conductivity. Such properties makepossible the use of the alloys for springs, electrical contactcomponents, welding rods, and the like. These desirable properties areimparted to the copper by incorporating therewith from about 1% to about2% beryllium metal, and in addition, about 0.20% to about 0.40% ofeither cobalt or nickel, or mixtures thereof.

Known alloys of commercial importance in the berylliumcopper alloy artare copper based, and contain about 2% beryllium metal, and about 0.20%to about 0.40% of either cobalt or nickel, or mixtures thereof.

Because of the high cost of these commercial alloys, it has long been anobjective of many workers in the beryllium-copper alloy art to obtainthe mechanical properties of these known alloys while partiallyreplacing the.

expensive beryllium metal content with other suitable and less expensivemetals capable of producing such properties in the alloy.

Various metals have been employed as partial substituents for theberyllium metal content, such as nickel, cobalt, zinc, silver, aluminum,and magnesium, but the mechanical properties of the alloys when thusmodified are not comparable to those of the known commercial alloysreferred to above.

In a later development in the art, a beryllium-copper alloy containingabout 1% beryllium was produced. This decrease of about 50% in theberyllium content of prior alloys was accomplished by replacing one halfof the original 2% beryllium content with Zinc. Since beryllium metal isthe most expensive component of bery lium copper alloys, thisdevelopment constituted a great advance in the art, particularly from aneconomic standpoint. The alloy containing 1% beryllium metal isdisclosed and claimed in Donachie US. Patent No. 2,789,899, issued April23, 1957.

In the file of the patent, the zinc content is said to be a matrixhardener for the copper and effective in amounts up to about 3.5%, byweight, of the composition. It is described as having no substantialeffect upon the properties of the alloys in amounts above 3.5%, althoughsome minor effect is shown from amounts of 3.5% up to about 5%.

Alloys having a beryllium content of less than 1%, by weight, of thecomposition, and retaining the same desirable mechanical properties assaid commercial alloy have been proposed, but none of them has beenfound to have mechanical properties comparable to those of the alloyscontaining 1% or 2% of beryllium.

The alloys of the present invention contain more than 10% and as high asabout 25% Zinc, from about a trace to about 1.00% tin, and metal fromthe class consisting of cobalt, nickel, and mixtures thereof, about0.10% to about 0.40%. These additions have made possible a reduction inberyllium metal content to a range between about 0.30% and 1.0%, whileproviding the mechanical properties comparable to those of commercialalloys containing from about 1.0% to about 2.0% beryllium.

Whenever quantities of cobalt are specified in the alloy composition,nickel, its Well-known equivalent, may be employed instead, in whole orpart.

It is an object of this invention to provide a copperbased alloycontaining beryllium, zinc, and optionally small proportions of tin andeither cobalt or nickel, the alloy having mechanical properties,including age hardening characteristics, comparable to the commercialalloys containing from about 1% to about 2% beryl lium metal.

It is a further object of the invention to provide cold Worked, solutionannealed, quenched, and age hardened copper-based alloys containing lessthan 1% beryllium, between about 10% and about 25% zinc, and minoramounts of tin and either cobalt or nickel, or mixtures thereof, andoptionally tin in small amounts, said alloys having mechanicalproperties comparable to age-hardenable commercial alloys containingfrom about 1% up to about 2% beryllium.

It is a still further object of the invention to provide suchcopper-based alloys having tensile and elongation properties superior tothose specified for Phosphor bronze.

Another object is to provide alloys of the above composition which arecapable of being rolled, drawn, extruded, forged, and pressed, by knowntechniques, without deterioration of their original mechanicalproperties.

The alloys of the present invention offer a further advantage in thatwhen certain kinds of metal scrap are employed in producing thecomposition, the method of combining the various metallic components toprovide the final composition does not require rigid control, becausethe components of the scrap, generally considered undesirable for alloysof optimum mechanical properties, are beneficial as metal components ofthe present alloy.

These and other objects and advantages of the invention will be obviousfrom the following description.

The essential constituents of the present alloys are broadly thefollowing:

Range, weight percent Be 0.30-1.10 Co 0.07-0.40 Zn 10.0025.00 SnTrace-1.00 Cu Balance More specifically, the alloys fallwithin thefollowing range:

Tin in amounts of from a trace to about 1.00% often unavoidablyintroduced as part of the scrap added to the charge, has no deleteriouseffect on the mechanical prop erties of the alloy. However, it isdesirable to maintain the tin in a range from about a trace to about0.85%, as alloys containing more than about 0.85%, although possessingsatisfactory mechanical properties, are not as amenable to fabricationoperations. Also, when the tin content is more than about 1.5%, ingotsof such composition tend to edge crack when rolled into strip.

The alloys may be produced by the conventional manner of melting apredetermined quantity of the elemental metals and casting the melt intoingots, or by any other conventional method of producing alloys. Whenprepared in a melt, the cast ingots may then be fabricated byconventional methods into sheets, bars, tubes, and wire.

in Table 1 below, examples of the alloy compositions and the mechanicalproperties developed by solution annealing and various degrees of coldWorking and heat treatment are shown. The test data Were obtained fromstrip which, in the solution annealed form, was 0.020" in thickness. Toobtain the strip, a melt of predetermined quantities of the elementalmetals was prepared and cast into ingots, which were first hot rolledand then cold rolled to a thickness of 0.09 and solution annealed. Theannealed strip of this thickness was then cold rolled in five passes toa thickness of 0.020", strand annealed at 1450" F. for about 1.5minutes, and quenched in water. The strip was then strand pickled, slitinto sections, one of which Was tested in the annealed condition, andthe others cold rolled to various degrees of reduced thickness and heattreated as shown in the table.

T he examples presented in the table show that the alloys containingfrom 0.65% to 0.85% beryllium and from about to about of Zinc in thesolution annealed and heat treated or age hardened conditions haveproperties comparable to those of the commercial beryllium-copper alloyscontaining from 1% to about 2% beryllium, and have superior mechanicalproperties to Phosphor bronze of the commercial grade A and springtemper types.

The expression balance substantially copper, as employed in the appendedclaims, does not exclude small quantities of addition metals or metalimpurities, such as aluminum, silver, and magnesium, in proportionsinsufiicient to substantially change thecharacteristics or mechanicalproperties of the said alloys.

TABLE 1 Compositions and Mechanical Propertiesof Beryllium- BronzeAlloys Mechanical Chemical Composition, Weight Properties Percent'Ienipcr Ultlmate Percent Tensile Elon- Strength, gation p.s.i. in 2Alloy Be Co Zn Sn Cu 0.32 Bal 0.56 0.15 20.6 0.35 Bel--.

0.51 20.7 0. 01 Bal 0. 58 15. 8 0. 48 Bel) Mechanical ChemicalComposition, Weight Properties Percent Temper Ultimate Percent TensileElon- Strength, gation p.s.i. i112" Alloy Be Co Zn Sn Cu 0. 20 0. 59Bel.

0. 0. 18 Bal.

0.75 0.26 1.07 Bah- 0. 77 0. l9 0. 45 Balsn 15.6 0. 01 Bald- 0. 38 0. 01BaL 0.94 0.45 Bal 0.98 0.46 25.7 0-01 Bal--.

NOTE.Tl1e following schedule defines the temper designations usedthroughout Table I Ann.Solution annealed at 1450 F. for one and onehalfminutes and quenched.

ATS0lution annealed at 1450 F. for one and one-,

half minutes, quenched, and heat treated at 600 F. for three hours.

%HSoluti0n annealed at 1450" F. for one and onehalf minutes, quenched,and reduced 20% in thickness by cold rolling.

HTSoluti0n annealed at 1450 F. for one and onehalf minutes, quenched,reduced 20% in thickness by field rolling, and heat treated at 600 F.for three ours.

HSoluti0n annealed at 1450 F. for one and onehalf minutes, quenched, andreduced 40% in thickness by cold rolling.

HTSo1utl0n annealed at 1450 F. for one and onehalf minutes, quenched,reduced 40% in thickness by cold rolling, and heat treated at 600 I for3 hrs.

XHSo1utl0n annealed at 1450 F. for one and onehalf minutes, quenched,reduced 50% in thickness by cold rolling.

XHT-S0luti0n annealed at 1450" F. for one and onehalf minutes, quenched,reduced 50% in thickness by cold rolling, and heat treated at 600 F. for3 hrs.

Having thus described my invention, 1 claim:

1. An alloy consisting essentially of about 0.30% to about 1.10% ofberyllium, about 0.10% to about 0.40% of metal from the group consistingof cobalt, nickel, and mixtures thereof, about 9% to about 25% of zinc,a trace References Cited in the file of this: patent UNITED STATESPATENTS Kinzel Jan. 31, 1939 Donachie Dec. 10, 1946 Driver June 17, 1947Johnson et a1 Feb. 26, 1957 Donachie Apr. 23, 1957 FOREIGN PATENTS GreatBritain May 29, 1940

1. AN ALLOY CONSISTING ESSENTIALLY OF ABOUT 0.30% TO ABOUT 1.10% OFBERYLLIUM, ABOUT 0.10% TO ABOUT 0.40% OF METAL FROM THE GROUP CONSISTINGOF C OBALT, NICKEL, AND MIXTURES THEREOF, ABOUT 9% TO ABOUT 25% OF ZINC,A TRACE TO ABOUT 1.0% OF TIN, AND THE BALANCE ESSENTIALLY COPPER.